| 摘要 |
PURPOSE:To speed up a DA output by connecting a 3rd switch means between a 1st power supply voltage supply terminal and a common connecting point, and controlling the 3rd switch means so as to be turned on for a transit period just after a 1st switch means turns from ON to OFF and a 2nd switch means turns OFF from ON. CONSTITUTION:Assuming that the switching speed of transistors(TRs) Q4-Q6, is faster by some degree than the time of a change of a node A, a TR Q1 is turned off just after a control signal goes from a low level to a high level and the node A reaches nearly 2V with a delay. Then the TRs Q2, Q5 are turned off and the TRs Q6 is turned on. IN such a case, the level of the node A rises from 2V, and the TR Q4 is turned on till the level reaches >=2.5V, resulting that the TR Q4 is turned on for a transit period just after the control signal goes from a low level to a high level and a current is supplied from a VDD so as to quicken the speed of the level of the node A from 2V to 3V. |
